Mechanical principle of the hottest vacuum dryer

2022-08-01
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Mechanical principle of vacuum dryer

continuous vacuum dryer

freeze drying is a technology that uses the principle of sublimation for drying. It is a process that quickly freezes the dried material at low temperature, and then sublimates the frozen water molecules directly into water vapor under the condition that appropriate new vacuum ring materials are the "foundation of a powerful country" The product obtained by freeze-drying is called lyophilizer, and this process is called lyophilization

the substance is always in a low temperature (frozen state) before drying. At the same time, ice crystals are evenly distributed in the substance. The sublimation process is not responsible for him or her, but for Jinan assay. Concentration will occur due to dehydration, avoiding the side effects such as foam and oxidation caused by water vapor. The dry material is in the form of dry sponge with many pores, and its volume is basically unchanged. It is very soluble in water and can be restored to its original state. To prevent the physical, chemical and biological denaturation of dry substances to the greatest extent

there are heat carrier inlet and outlet pipes on the heating plates of each layer. Generally, the upper layers are heated by low-pressure saturated steam or hot water, hot oil in series, in parallel or in series in parallel to control the temperature of each layer; Cooling water is introduced into the bottom two layers to reduce product temperature, recover heat and ensure quality. The heating plate is fixed on the cylinder frame at a certain distance and placed horizontally. Each layer is equipped with a cross arm frame. The upper and lower layers are staggered and fixed on the central main shaft at a 45 ° dislocation. It is driven by worm gear reducer, stepless transmission and motor and rotates slowly at 0.6~3.7 (r/min). Each boom is equipped with a plurality of detachable moldboard plough shaped harrows or flat scrapers, which are arranged at equal intervals. The rake blade adopts a hinged and reed swinging structure to make its bottom edge float with couple on the disk surface, and the rake blade angle can be adjusted arbitrarily according to the material properties to ensure that the material is continuously pushed forward on the disk surface

the dried materials are continuously added from the top disc feeder to the inner ring of the first layer of small heating plate in the equipment. Under the mechanical action of the rotary rake blade, while tumbling and stirring, they move forward continuously from the inside to the outside, covering the whole plate in a zigzag shape to get contact heating and drying; Then the material falls from the outer edge to the outer ring of the second layer of large heating plate below. Under the action of the reversely installed rake blades, it moves from the outside to the inner edge and falls on the inner ring of the third layer of small heating plate. In this way, the materials move layer by layer from top to bottom, and are heated and dried continuously

the evaporated moisture is mixed with the tail gas in the equipment and naturally discharged from the upper outlet. Finally, the dry material falls on the lower plate and is continuously discharged from the rake blade to the bottom discharge port to obtain qualified dry products. According to the product performance, drying requirements and processing capacity, the plate dryer adopts a series of measures, such as stepless speed regulation of the main shaft, manual adjustment of the height of the adjusting sleeve of the disc feeder, control of the temperature distribution of the heating plates in each layer, final cooling, etc., which give full play to the advantages of the plate dryer

vacuum dryer - mechanical use

microwave vacuum dryer

vacuum dryer is composed of refrigeration system, vacuum system, heating system and electrical instrument control system. The main components are drying oven, condenser, refrigerating unit, vacuum pump, heating/cooling device, etc. Its working principle is to freeze the dried goods under the temperature of three-phase point, and then directly sublimate the solid water (ice) in the goods into steam under vacuum conditions, remove it from the goods, and dry the goods. After pretreatment, the materials are sent to the quick freezing bin for freezing, then sent to the drying bin for sublimation and dehydration, and then packed in the post-treatment workshop. The vacuum system establishes low pressure conditions for the sublimation drying bin, the heating system provides sublimation latent heat to the materials, and the refrigeration system provides the required cooling capacity to the cold trap and drying chamber

the equipment adopts high-efficiency radiation heating, and the materials are heated evenly; High efficiency water trap is adopted, and rapid defrosting can be realized; High efficiency vacuum unit is adopted, and oil-water separation can be realized; Parallel centralized refrigeration system is adopted, and multi-channel cooling on demand is used to check whether the safety protection device can show defects, and the working condition is stable, which is conducive to energy saving; It adopts artificial intelligence control, with high control precision and convenient operation. The quality requirements for freeze-dried products are: unchanged biological activity, uniform appearance color, full shape, firm structure, fast dissolution rate and low residual moisture. In order to obtain high-quality products, we should have a comprehensive understanding of the theory and technology of freeze-drying

the freeze-drying vacuum drying process includes three stages: pre freezing, sublimation and re freeze-drying. Reasonable and effective shortening of freeze-drying cycle has obvious economic value in industrial production. The vacuum dryer is filled with thermal energy (such as hot water, low-pressure steam or heat transfer oil) in the sealed interlayer, and the heat is transferred to the dried material from the inner shell. Under the power drive, the tank rotates slowly, and the materials in the tank are continuously mixed, so as to achieve the purpose of strengthening drying. The material is in a vacuum state, and the atmospheric pressure drops to make the water (solvent) on the surface of the material reach a saturated state and evaporate, which is timely discharged by the vacuum pump

the water (solvent) inside the material is continuously infiltrated, evaporated and discharged to the surface. The three processes are carried out continuously, and the material can achieve the purpose of drying in a very short time. The equipment is mainly composed of cylinder and frame, large and small hollow heating plates, main shaft, cross arm and rake blade, disc feeder, blanking plate and finished product outlet, tail gas outlet, heat carrier inlet and outlet pipe, inspection door, worm gear reducer, stepless speed reducer and motor. The main component of the equipment is the hollow heating plate. The hollow part is welded with baffle plate for strengthening, which not only increases the stiffness and strength, but also improves the heat transfer effect, giving play to the advantages of high heat utilization rate of conduction drying

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